Some communication systems operate mobile communication terminals intermittently, such as in a discontinuous reception (DRX) mode in which the terminal activates its receiver for short durations in accordance with a specified cycle. DRX operation in Global System for Mobile communications (GSM) is specified, for example, in “3rd Generation Partnership Project; Technical Specification Group GSM/EDGE Radio Access Network; Functions Related to Mobile Station (MS) in Idle Mode and Group Receive Mode (Release 10),” TS 43.022, version 9.2.0, September, 2010, which is incorporated herein by reference.
In Universal Mobile Telecommunications System (UMTS), the DRX mode is specified in “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; User Equipment (UE) Procedures in Idle Mode and Procedures for Cell Reselection in Connected Mode (Release 9),” TS 25.304, version 9.3.0, September, 2010, which is incorporated herein by reference.
DRX operation in Long-Term Evolution (LTE) systems is specified in “3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) Procedures in Idle Mode (Release 9),” TS 36.304, version 9.5.0, December, 2010, which is incorporated herein by reference.
Some wireless communication terminals use crystal oscillators as reference sources, such as for generating a reference clock for producing Local Oscillator (LO) signals and/or as a time base for various signal processing operations. When a terminal operates intermittently, such as in DRX mode, high accuracy may be required from the terminal's reference clock source.
The description above is presented as a general overview of related art in this field and should not be construed as an admission that any of the information it contains constitutes prior art against the present patent application.